Story: I was trying to make more room on my dual boot hard drive. I have Backtrack 5 installed as the default and Windows 7 as well. Another partition is a Lenovo Recovery that took up 14GB. I deleted it in Disk Management and restarted my system. Now my screen shows this when I boot up:
Error: Unknown filesystem
Grub rescue>

After reading around the net, I think my grub loader was corrupted. I proceeded to redownload and make an external hard drive boot Backtrack 5 from it. I went to edit the BIOS Setup so that my External Hard Drive (which has BT5 installed) boot first. Lo and behold the arrow keys do not work in the BIOS Setup. I tried connecting a USB Keyboard to my computer and still they refuse to work. Without being able to select the external hard drive to boot from, I am at a loss of options of what to do (besides erasing everything and starting over).

End goal: Can I restore the Grub Loader so everything goes back to normal? Also, how do I get my BIOS to recognize arrow keys?

Computer: Lenovo ThinkPad X120e
2GB PC3-10600 1333MHz DDR3 SDRAM
320GB Hard Drive
AMD Fusion E-350 Dual-Core 1.60GHz Processor
Windows 7 Home Premium 32Bit
(I later installed Backtrack 5 KDE as a dual-boot)

External Hard Drive:
Western Digital My Passport Essential 250 GB USB 2.0 Portable External Hard Drive (Midnight Black)
I installed Backtrack 5 KDE using Unetbootin and can confirm that it works properly.

Any help would be appreciated.